Exposure to high temperatures on drilling fluids causes increased coagulation, which leads to loss of aggregate and kinetic stability. In drilling practice, the coagulation of drilling mud is caused by an increase in the concentration of the solid phase, the aggression of electrolytes and an increase in temperature. These factors determine the different forms and levels of coagulation processes. When the solution is heated, the peptization of clay particles increases, but the viscosity of the dispersion medium and the protective effect of stabilizers decrease. Depending on the concentration of the solid phase, the aggressiveness of the salt, the presence of a stabilizer and its properties, exposure to high temperature can lead to thinning or thickening of the coagulation, but in any case, the filtration rate increases. Even a small concentration of salts when heated causes coagulation, which is not noticeable at moderate temperatures. Currently, there are no heat-resistant inhibiting drilling fluids for penetration into unstable clay rocks that prevent their hydration and swelling, on the one hand, and heat-resistant saline-saturated drilling fluids with high density for penetration into salt deposits that are resistant to polyvalent cations, on the other hand, a limiting factor is deep drilling in many promising oil and gas regions.
Gazprom VNIIGAZ LLC has developed the Katburr multimedia system, which eliminates the disadvantages of traditional polyanion and non-ionic solutions. Polycation systems is a new direction in the field of drilling fluids. Weighted modifications of polycationic solutions resistant to temperature aggression of 200°C or more have been developed and studied for well construction: a salt-saturated composition for subsalt Jurassic deposits in the central part of the North Caucasus, a hydrogen sulfide-resistant composition for Devonian sediments of the Astrakhan gas condensate field, and a heavier composition for Middle Jurassic deposits of the western part of the North Caucasus.
References
1. Kister E.G., Khimicheskaya obrabotka burovykh rastvorov (Chemical treatment of drilling fluids), Moscow: Nedra Publ., 1972, 392 p.
2. Kister E.G., Pondoeva E.I., Issledovanie mekhanizma stabilizatsii glinistykh suspenziy khromatami (Study of the mechanism of stabilization of clay suspensions by chromates), Proceedings of VNIIBT, 1971, v. 27, pp. 95–103.
3. Gaydarov A.M., Khubbatov A.A., Khrabrov D.V. et al., "CatBurr" polycation systems is a new development in the field of drill muds (In Russ.), Stroitel'stvo neftyanykh i gazovykh skvazhin na sushe i na more, 2017, no. 7, pp. 36–49.
4. Gaydarov M.M-R., Khubbatov A.A., Gaydarov A.M. et al., “Katburr" polycationic drilling fluids and prospects for their use (In Russ.), Stroitel'stvo neftyanykh i gazovykh skvazhin na sushe i na more, 2019, no. 7, pp. 19–25.
5. Gaydarov A.M., Khubbatov A.A., Norov A.D. et al., The use of polycationic drilling fluids in the Astrakhanskoye gas and condensate field (In Russ.), Vestnik assotsiatsii burovykh podryadchikov, 2016, no. 2, pp. 20–23.
6. Gaydarov A.M., Khubbatov A.A., Norov A.D., Gaydarov M.M–R., The experience of the application of weighted cationic drilling muds (In Russ.), Heftyanoe khozyaystvo = Oil Industry, 2016, no. 9, pp. 44–48.
7. Khubbatov A.A., Gaydarov A.M., Khrabrov D.V. et al., Application of polycationic drilling muds when drilling salt-bearing deposits in the Pre-Caspian Depression (In Russ.), Stroitel'stvo neftyanykh i gazovykh skvazhin na sushe i na more, 2017, no. 1, pp. 33–39.
8. Gaydarov A.M., Khubbatov A.A., Gaydarov M.M-R., Experience with the application of Katburr modifications at the Astrakhan gas condensate field (In Russ.), Inzhener-neftyanik, 2018, no. 2, pp. 15–21.
